[libc++] Add missing iterator requirement checks in the PSTL

libcxx/include/__algorithm/pstl_any_all_none_of.h

@@ -60,7 +60,7 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI bool
 any_of(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) {
-  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "any_of requires a ForwardIterator");
   auto __res = std::__any_of(__policy, std::move(__first), std::move(__last), std::move(__pred));
   if (!__res)
     std::__throw_bad_alloc();
@@ -99,7 +99,7 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI bool
 all_of(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Pred __pred) {
-  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "all_of requires a ForwardIterator");
   auto __res = std::__all_of(__policy, std::move(__first), std::move(__last), std::move(__pred));
   if (!__res)
     std::__throw_bad_alloc();
@@ -136,7 +136,7 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI bool
 none_of(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Pred __pred) {
-  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "none_of requires a ForwardIterator");
   auto __res = std::__none_of(__policy, std::move(__first), std::move(__last), std::move(__pred));
   if (!__res)
     std::__throw_bad_alloc();

libcxx/include/__algorithm/pstl_copy.h

@@ -16,6 +16,7 @@
 #include <__config>
 #include <__functional/identity.h>
 #include <__iterator/concepts.h>
+#include <__iterator/cpp17_iterator_concepts.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/is_constant_evaluated.h>
 #include <__type_traits/is_execution_policy.h>
@@ -67,6 +68,12 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI _ForwardOutIterator
 copy(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _ForwardOutIterator __result) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(
+      _ForwardIterator, "copy(first, last, result) requires [first, last) to be ForwardIterators");
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(
+      _ForwardOutIterator, "copy(first, last, result) requires result to be a ForwardIterator");
+  _LIBCPP_REQUIRE_CPP17_OUTPUT_ITERATOR(
+      _ForwardOutIterator, decltype(*__first), "copy(first, last, result) requires result to be an OutputIterator");
   auto __res = std::__copy(__policy, std::move(__first), std::move(__last), std::move(__result));
   if (!__res)
     std::__throw_bad_alloc();
@@ -106,6 +113,12 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI _ForwardOutIterator
 copy_n(_ExecutionPolicy&& __policy, _ForwardIterator __first, _Size __n, _ForwardOutIterator __result) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(
+      _ForwardIterator, "copy_n(first, n, result) requires first to be a ForwardIterator");
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(
+      _ForwardOutIterator, "copy_n(first, n, result) requires result to be a ForwardIterator");
+  _LIBCPP_REQUIRE_CPP17_OUTPUT_ITERATOR(
+      _ForwardOutIterator, decltype(*__first), "copy_n(first, n, result) requires result to be an OutputIterator");
   auto __res = std::__copy_n(__policy, std::move(__first), std::move(__n), std::move(__result));
   if (!__res)
     std::__throw_bad_alloc();

libcxx/include/__algorithm/pstl_count.h

@@ -17,6 +17,7 @@
 #include <__atomic/atomic.h>
 #include <__config>
 #include <__functional/operations.h>
+#include <__iterator/cpp17_iterator_concepts.h>
 #include <__iterator/iterator_traits.h>
 #include <__numeric/pstl_transform_reduce.h>
 #include <__type_traits/enable_if.h>
@@ -70,6 +71,8 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI __iter_diff_t<_ForwardIterator>
 count_if(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(
+      _ForwardIterator, "count_if(first, last, pred) requires [first, last) to be ForwardIterators");
   auto __res = std::__count_if(__policy, std::move(__first), std::move(__last), std::move(__pred));
   if (!__res)
     std::__throw_bad_alloc();
@@ -106,6 +109,8 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI __iter_diff_t<_ForwardIterator>
 count(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(
+      _ForwardIterator, "count(first, last, val) requires [first, last) to be ForwardIterators");
   auto __res = std::__count(__policy, std::move(__first), std::move(__last), __value);
   if (!__res)
     std::__throw_bad_alloc();

libcxx/include/__algorithm/pstl_equal.h

@@ -13,6 +13,7 @@
 #include <__algorithm/pstl_frontend_dispatch.h>
 #include <__config>
 #include <__functional/operations.h>
+#include <__iterator/cpp17_iterator_concepts.h>
 #include <__iterator/iterator_traits.h>
 #include <__numeric/pstl_transform_reduce.h>
 #include <__utility/move.h>
@@ -74,6 +75,8 @@ equal(_ExecutionPolicy&& __policy,
       _ForwardIterator1 __last1,
       _ForwardIterator2 __first2,
       _Pred __pred) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator1, "equal requires ForwardIterators");
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator2, "equal requires ForwardIterators");
   auto __res = std::__equal(__policy, std::move(__first1), std::move(__last1), std::move(__first2), std::move(__pred));
   if (!__res)
     std::__throw_bad_alloc();
@@ -86,6 +89,8 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<__remove_cvref_t<_ExecutionPolicy>>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI bool
 equal(_ExecutionPolicy&& __policy, _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator1, "equal requires ForwardIterators");
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator2, "equal requires ForwardIterators");
   return std::equal(__policy, std::move(__first1), std::move(__last1), std::move(__first2), std::equal_to{});
 }
 
@@ -145,6 +150,8 @@ equal(_ExecutionPolicy&& __policy,
       _ForwardIterator2 __first2,
       _ForwardIterator2 __last2,
       _Pred __pred) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator1, "equal requires ForwardIterators");
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator2, "equal requires ForwardIterators");
   auto __res = std::__equal(
       __policy, std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2), std::move(__pred));
   if (!__res)
@@ -162,6 +169,8 @@ equal(_ExecutionPolicy&& __policy,
       _ForwardIterator1 __last1,
       _ForwardIterator2 __first2,
       _ForwardIterator2 __last2) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator1, "equal requires ForwardIterators");
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator2, "equal requires ForwardIterators");
   return std::equal(
       __policy, std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2), std::equal_to{});
 }

libcxx/include/__algorithm/pstl_fill.h

@@ -43,7 +43,6 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI optional<__empty>
 __fill(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) noexcept {
-  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
   return std::__pstl_frontend_dispatch(
       _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_fill, _RawPolicy),
       [&](_ForwardIterator __g_first, _ForwardIterator __g_last, const _Tp& __g_value) {
@@ -63,7 +62,7 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI void
 fill(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
-  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "fill requires ForwardIterators");
   if (!std::__fill(__policy, std::move(__first), std::move(__last), __value))
     std::__throw_bad_alloc();
 }
@@ -79,7 +78,6 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__empty>
 __fill_n(_ExecutionPolicy&& __policy, _ForwardIterator&& __first, _SizeT&& __n, const _Tp& __value) noexcept {
-  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
   return std::__pstl_frontend_dispatch(
       _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_fill_n, _RawPolicy),
       [&](_ForwardIterator __g_first, _SizeT __g_n, const _Tp& __g_value) {
@@ -102,7 +100,7 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI void
 fill_n(_ExecutionPolicy&& __policy, _ForwardIterator __first, _SizeT __n, const _Tp& __value) {
-  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "fill_n requires ForwardIterators");
   if (!std::__fill_n(__policy, std::move(__first), std::move(__n), __value))
     std::__throw_bad_alloc();
 }

libcxx/include/__algorithm/pstl_find.h

@@ -50,7 +50,7 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI _ForwardIterator
 find_if(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) {
-  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "find_if requires ForwardIterators");
   auto __res = std::__find_if(__policy, std::move(__first), std::move(__last), std::move(__pred));
   if (!__res)
     std::__throw_bad_alloc();
@@ -88,7 +88,7 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI _ForwardIterator
 find_if_not(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) {
-  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "find_if_not requires ForwardIterators");
   auto __res = std::__find_if_not(__policy, std::move(__first), std::move(__last), std::move(__pred));
   if (!__res)
     std::__throw_bad_alloc();
@@ -125,7 +125,7 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI _ForwardIterator
 find(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
-  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "find requires ForwardIterators");
   auto __res = std::__find(__policy, std::move(__first), std::move(__last), __value);
   if (!__res)
     std::__throw_bad_alloc();

libcxx/include/__algorithm/pstl_for_each.h

@@ -53,7 +53,7 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI void
 for_each(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Function __func) {
-  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "for_each requires ForwardIterators");
   if (!std::__for_each(__policy, std::move(__first), std::move(__last), std::move(__func)))
     std::__throw_bad_alloc();
 }
@@ -93,7 +93,7 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI void
 for_each_n(_ExecutionPolicy&& __policy, _ForwardIterator __first, _Size __size, _Function __func) {
-  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "for_each_n requires a ForwardIterator");
   auto __res = std::__for_each_n(__policy, std::move(__first), std::move(__size), std::move(__func));
   if (!__res)
     std::__throw_bad_alloc();

libcxx/include/__algorithm/pstl_generate.h

@@ -42,7 +42,6 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__empty>
 __generate(_ExecutionPolicy&& __policy, _ForwardIterator&& __first, _ForwardIterator&& __last, _Generator&& __gen) {
-  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
   return std::__pstl_frontend_dispatch(
       _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_generate, _RawPolicy),
       [&__policy](_ForwardIterator __g_first, _ForwardIterator __g_last, _Generator __g_gen) {
@@ -63,7 +62,7 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI void
 generate(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Generator __gen) {
-  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "generate requires ForwardIterators");
   if (!std::__generate(__policy, std::move(__first), std::move(__last), std::move(__gen)))
     std::__throw_bad_alloc();
 }
@@ -100,7 +99,7 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI void
 generate_n(_ExecutionPolicy&& __policy, _ForwardIterator __first, _Size __n, _Generator __gen) {
-  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator);
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "generate_n requires a ForwardIterator");
   if (!std::__generate_n(__policy, std::move(__first), std::move(__n), std::move(__gen)))
     std::__throw_bad_alloc();
 }

libcxx/include/__algorithm/pstl_is_partitioned.h

@@ -14,6 +14,7 @@
 #include <__algorithm/pstl_find.h>
 #include <__algorithm/pstl_frontend_dispatch.h>
 #include <__config>
+#include <__iterator/cpp17_iterator_concepts.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/is_execution_policy.h>
 #include <__type_traits/remove_cvref.h>
@@ -62,6 +63,7 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI bool
 is_partitioned(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "is_partitioned requires ForwardIterators");
   auto __res = std::__is_partitioned(__policy, std::move(__first), std::move(__last), std::move(__pred));
   if (!__res)
     std::__throw_bad_alloc();

libcxx/include/__algorithm/pstl_merge.h

@@ -12,6 +12,7 @@
 #include <__algorithm/pstl_backend.h>
 #include <__config>
 #include <__functional/operations.h>
+#include <__iterator/cpp17_iterator_concepts.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/is_execution_policy.h>
 #include <__type_traits/remove_cvref.h>
@@ -70,6 +71,10 @@ merge(_ExecutionPolicy&& __policy,
       _ForwardIterator2 __last2,
       _ForwardOutIterator __result,
       _Comp __comp = {}) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator1, "merge requires ForwardIterators");
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator2, "merge requires ForwardIterators");
+  _LIBCPP_REQUIRE_CPP17_OUTPUT_ITERATOR(_ForwardOutIterator, decltype(*__first1), "merge requires an OutputIterator");
+  _LIBCPP_REQUIRE_CPP17_OUTPUT_ITERATOR(_ForwardOutIterator, decltype(*__first2), "merge requires an OutputIterator");
   auto __res = std::__merge(
       __policy,
       std::move(__first1),

libcxx/include/__algorithm/pstl_move.h

@@ -15,6 +15,7 @@
 #include <__algorithm/pstl_transform.h>
 #include <__config>
 #include <__functional/identity.h>
+#include <__iterator/cpp17_iterator_concepts.h>
 #include <__iterator/iterator_traits.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/is_constant_evaluated.h>
@@ -69,6 +70,10 @@ template <class _ExecutionPolicy,
           enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
 _LIBCPP_HIDE_FROM_ABI _ForwardOutIterator
 move(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _ForwardOutIterator __result) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "move requires ForwardIterators");
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardOutIterator, "move requires an OutputIterator");
+  _LIBCPP_REQUIRE_CPP17_OUTPUT_ITERATOR(
+      _ForwardOutIterator, decltype(std::move(*__first)), "move requires an OutputIterator");
   auto __res = std::__move(__policy, std::move(__first), std::move(__last), std::move(__result));
   if (!__res)
     std::__throw_bad_alloc();

libcxx/include/__algorithm/pstl_replace.h

@@ -14,6 +14,7 @@
 #include <__algorithm/pstl_frontend_dispatch.h>
 #include <__algorithm/pstl_transform.h>
 #include <__config>
+#include <__iterator/cpp17_iterator_concepts.h>
 #include <__iterator/iterator_traits.h>
 #include <__type_traits/enable_if.h>
 #include <__type_traits/remove_cvref.h>
@@ -74,6 +75,7 @@ replace_if(_ExecutionPolicy&& __policy,
            _ForwardIterator __last,
            _Pred __pred,
            const _Tp& __new_value) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "replace_if requires ForwardIterators");
   auto __res = std::__replace_if(__policy, std::move(__first), std::move(__last), std::move(__pred), __new_value);
   if (!__res)
     std::__throw_bad_alloc();
@@ -121,6 +123,7 @@ replace(_ExecutionPolicy&& __policy,
         _ForwardIterator __last,
         const _Tp& __old_value,
         const _Tp& __new_value) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "replace requires ForwardIterators");
   if (!std::__replace(__policy, std::move(__first), std::move(__last), __old_value, __new_value))
     std::__throw_bad_alloc();
 }
@@ -177,6 +180,11 @@ _LIBCPP_HIDE_FROM_ABI void replace_copy_if(
     _ForwardOutIterator __result,
     _Pred __pred,
     const _Tp& __new_value) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "replace_copy_if requires ForwardIterators");
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardOutIterator, "replace_copy_if requires ForwardIterators");
+  _LIBCPP_REQUIRE_CPP17_OUTPUT_ITERATOR(
+      _ForwardOutIterator, decltype(*__first), "replace_copy_if requires an OutputIterator");
+  _LIBCPP_REQUIRE_CPP17_OUTPUT_ITERATOR(_ForwardOutIterator, const _Tp&, "replace_copy requires an OutputIterator");
   if (!std::__replace_copy_if(
           __policy, std::move(__first), std::move(__last), std::move(__result), std::move(__pred), __new_value))
     std::__throw_bad_alloc();
@@ -233,6 +241,11 @@ _LIBCPP_HIDE_FROM_ABI void replace_copy(
     _ForwardOutIterator __result,
     const _Tp& __old_value,
     const _Tp& __new_value) {
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardIterator, "replace_copy requires ForwardIterators");
+  _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(_ForwardOutIterator, "replace_copy requires ForwardIterators");
+  _LIBCPP_REQUIRE_CPP17_OUTPUT_ITERATOR(
+      _ForwardOutIterator, decltype(*__first), "replace_copy requires an OutputIterator");
+  _LIBCPP_REQUIRE_CPP17_OUTPUT_ITERATOR(_ForwardOutIterator, const _Tp&, "replace_copy requires an OutputIterator");
   if (!std::__replace_copy(
           __policy, std::move(__first), std::move(__last), std::move(__result), __old_value, __new_value))
     std::__throw_bad_alloc();